diff --git a/src/pkg/image/png/writer.go b/src/pkg/image/png/writer.go index a27586f2394..d770cfad5f0 100644 --- a/src/pkg/image/png/writer.go +++ b/src/pkg/image/png/writer.go @@ -174,7 +174,7 @@ func (e *encoder) Write(b []byte) (int, os.Error) { // Chooses the filter to use for encoding the current row, and applies it. // The return value is the index of the filter and also of the row in cr that has had it applied. -func filter(cr [][]byte, pr []byte, bpp int) int { +func filter(cr *[nFilter][]byte, pr []byte, bpp int) int { // We try all five filter types, and pick the one that minimizes the sum of absolute differences. // This is the same heuristic that libpng uses, although the filters are attempted in order of // estimated most likely to be minimal (ftUp, ftPaeth, ftNone, ftSub, ftAverage), rather than @@ -304,7 +304,7 @@ func writeImage(w io.Writer, m image.Image, cb int) os.Error { // The +1 is for the per-row filter type, which is at cr[*][0]. b := m.Bounds() var cr [nFilter][]uint8 - for i := 0; i < len(cr); i++ { + for i := range cr { cr[i] = make([]uint8, 1+bpp*b.Dx()) cr[i][0] = uint8(i) } @@ -312,78 +312,84 @@ func writeImage(w io.Writer, m image.Image, cb int) os.Error { for y := b.Min.Y; y < b.Max.Y; y++ { // Convert from colors to bytes. + i := 1 switch cb { case cbG8: for x := b.Min.X; x < b.Max.X; x++ { c := image.GrayColorModel.Convert(m.At(x, y)).(image.GrayColor) - cr[0][x+1] = c.Y + cr[0][i] = c.Y + i++ } case cbTC8: // We have previously verified that the alpha value is fully opaque. cr0 := cr[0] if rgba != nil { yoff := y * rgba.Stride - xoff := 3*b.Min.X + 1 for _, color := range rgba.Pix[yoff+b.Min.X : yoff+b.Max.X] { - cr0[xoff] = color.R - cr0[xoff+1] = color.G - cr0[xoff+2] = color.B - xoff += 3 + cr0[i+0] = color.R + cr0[i+1] = color.G + cr0[i+2] = color.B + i += 3 } } else { for x := b.Min.X; x < b.Max.X; x++ { r, g, b, _ := m.At(x, y).RGBA() - cr0[3*x+1] = uint8(r >> 8) - cr0[3*x+2] = uint8(g >> 8) - cr0[3*x+3] = uint8(b >> 8) + cr0[i+0] = uint8(r >> 8) + cr0[i+1] = uint8(g >> 8) + cr0[i+2] = uint8(b >> 8) + i += 3 } } case cbP8: rowOffset := y * paletted.Stride - copy(cr[0][b.Min.X+1:], paletted.Pix[rowOffset+b.Min.X:rowOffset+b.Max.X]) + copy(cr[0][1:], paletted.Pix[rowOffset+b.Min.X:rowOffset+b.Max.X]) case cbTCA8: // Convert from image.Image (which is alpha-premultiplied) to PNG's non-alpha-premultiplied. for x := b.Min.X; x < b.Max.X; x++ { c := image.NRGBAColorModel.Convert(m.At(x, y)).(image.NRGBAColor) - cr[0][4*x+1] = c.R - cr[0][4*x+2] = c.G - cr[0][4*x+3] = c.B - cr[0][4*x+4] = c.A + cr[0][i+0] = c.R + cr[0][i+1] = c.G + cr[0][i+2] = c.B + cr[0][i+3] = c.A + i += 4 } case cbG16: for x := b.Min.X; x < b.Max.X; x++ { c := image.Gray16ColorModel.Convert(m.At(x, y)).(image.Gray16Color) - cr[0][2*x+1] = uint8(c.Y >> 8) - cr[0][2*x+2] = uint8(c.Y) + cr[0][i+0] = uint8(c.Y >> 8) + cr[0][i+1] = uint8(c.Y) + i += 2 } case cbTC16: + // We have previously verified that the alpha value is fully opaque. for x := b.Min.X; x < b.Max.X; x++ { - // We have previously verified that the alpha value is fully opaque. r, g, b, _ := m.At(x, y).RGBA() - cr[0][6*x+1] = uint8(r >> 8) - cr[0][6*x+2] = uint8(r) - cr[0][6*x+3] = uint8(g >> 8) - cr[0][6*x+4] = uint8(g) - cr[0][6*x+5] = uint8(b >> 8) - cr[0][6*x+6] = uint8(b) + cr[0][i+0] = uint8(r >> 8) + cr[0][i+1] = uint8(r) + cr[0][i+2] = uint8(g >> 8) + cr[0][i+3] = uint8(g) + cr[0][i+4] = uint8(b >> 8) + cr[0][i+5] = uint8(b) + i += 6 } case cbTCA16: // Convert from image.Image (which is alpha-premultiplied) to PNG's non-alpha-premultiplied. for x := b.Min.X; x < b.Max.X; x++ { c := image.NRGBA64ColorModel.Convert(m.At(x, y)).(image.NRGBA64Color) - cr[0][8*x+1] = uint8(c.R >> 8) - cr[0][8*x+2] = uint8(c.R) - cr[0][8*x+3] = uint8(c.G >> 8) - cr[0][8*x+4] = uint8(c.G) - cr[0][8*x+5] = uint8(c.B >> 8) - cr[0][8*x+6] = uint8(c.B) - cr[0][8*x+7] = uint8(c.A >> 8) - cr[0][8*x+8] = uint8(c.A) + cr[0][i+0] = uint8(c.R >> 8) + cr[0][i+1] = uint8(c.R) + cr[0][i+2] = uint8(c.G >> 8) + cr[0][i+3] = uint8(c.G) + cr[0][i+4] = uint8(c.B >> 8) + cr[0][i+5] = uint8(c.B) + cr[0][i+6] = uint8(c.A >> 8) + cr[0][i+7] = uint8(c.A) + i += 8 } } // Apply the filter. - f := filter(cr[0:nFilter], pr, bpp) + f := filter(&cr, pr, bpp) // Write the compressed bytes. _, err = zw.Write(cr[f]) diff --git a/src/pkg/image/png/writer_test.go b/src/pkg/image/png/writer_test.go index 6b054aaa893..271519a11f7 100644 --- a/src/pkg/image/png/writer_test.go +++ b/src/pkg/image/png/writer_test.go @@ -5,9 +5,9 @@ package png import ( + "bytes" "fmt" "image" - "io" "io/ioutil" "os" "testing" @@ -15,21 +15,38 @@ import ( func diff(m0, m1 image.Image) os.Error { b0, b1 := m0.Bounds(), m1.Bounds() - if !b0.Eq(b1) { + if !b0.Size().Eq(b1.Size()) { return fmt.Errorf("dimensions differ: %v vs %v", b0, b1) } + dx := b1.Min.X - b0.Min.X + dy := b1.Min.Y - b0.Min.Y for y := b0.Min.Y; y < b0.Max.Y; y++ { for x := b0.Min.X; x < b0.Max.X; x++ { - r0, g0, b0, a0 := m0.At(x, y).RGBA() - r1, g1, b1, a1 := m1.At(x, y).RGBA() + c0 := m0.At(x, y) + c1 := m1.At(x+dx, y+dy) + r0, g0, b0, a0 := c0.RGBA() + r1, g1, b1, a1 := c1.RGBA() if r0 != r1 || g0 != g1 || b0 != b1 || a0 != a1 { - return fmt.Errorf("colors differ at (%d, %d): %v vs %v", x, y, m0.At(x, y), m1.At(x, y)) + return fmt.Errorf("colors differ at (%d, %d): %v vs %v", x, y, c0, c1) } } } return nil } +func encodeDecode(m image.Image) (image.Image, os.Error) { + b := bytes.NewBuffer(nil) + err := Encode(b, m) + if err != nil { + return nil, err + } + m, err = Decode(b) + if err != nil { + return nil, err + } + return m, nil +} + func TestWriter(t *testing.T) { // The filenames variable is declared in reader_test.go. names := filenames @@ -44,26 +61,16 @@ func TestWriter(t *testing.T) { t.Error(fn, err) continue } - // Read the image again, and push it through a pipe that encodes at the write end, and decodes at the read end. - pr, pw := io.Pipe() - defer pr.Close() - go func() { - defer pw.Close() - m1, err := readPng(qfn) - if err != nil { - t.Error(fn, err) - return - } - err = Encode(pw, m1) - if err != nil { - t.Error(fn, err) - return - } - }() - m2, err := Decode(pr) + // Read the image again, encode it, and decode it. + m1, err := readPng(qfn) if err != nil { t.Error(fn, err) - continue + return + } + m2, err := encodeDecode(m1) + if err != nil { + t.Error(fn, err) + return } // Compare the two. err = diff(m0, m2) @@ -74,6 +81,26 @@ func TestWriter(t *testing.T) { } } +func TestSubimage(t *testing.T) { + m0 := image.NewRGBA(256, 256) + for y := 0; y < 256; y++ { + for x := 0; x < 256; x++ { + m0.Set(x, y, image.RGBAColor{uint8(x), uint8(y), 0, 255}) + } + } + m0.Rect = image.Rect(50, 30, 250, 130) + m1, err := encodeDecode(m0) + if err != nil { + t.Error(err) + return + } + err = diff(m0, m1) + if err != nil { + t.Error(err) + return + } +} + func BenchmarkEncodePaletted(b *testing.B) { b.StopTimer() img := image.NewPaletted(640, 480,